The present invention is broadly applicable to cleaning apparatuses of the type employed for cleaning heat exchange surfaces to remove soot, slag, ash and other accumulated deposits thereon to maintain efficiency in their operation. The improved nozzle construction is particularly applicable, but not necessarily limited to automatic sootblower cleaning devices such as long retracting-type sootblowers as generally described in U.S. Pat. No. 3,608,125; short retracting-type sootblowers such as described in U.S. Pat. No. 3,377,026; and an automatic sootblower for alternatively discharging a liquid and a gaseous blowing medium as described in U.S. Pat. No. 4,209,028 the teachings of which are incorporated herein by reference.
A continuing problem associated with cleaning devices of the types to which the present invention is applicable is the tendency of the jet or stream of fluid blowing medium discharged from the nozzle to loose its integrity between the point of discharge and impingement upon the surface to be cleaned due to the disturbance of the stream by gas currents present in the heat exchange apparatuses, such as high pressure boilers, in which they are employed. Such disturbances result in a fanning out or spreading of the stream or jet resulting in a reduction in the average and maximum velocities of the stream such that a lower peak impact pressure (PIP) of the stream or jet at the point of impingement is obtained thereby reducing the effectiveness and efficiency of the cleaning operation. This problem is particularly pronounced at relatively extreme cleaning distances as frequently encountered in high capacity pressure boilers. The foregoing problem is further aggravated by the fact that optimum nozzle design and optimum nozzle inlet conditions are severly restricted by the limited space available in the lance tube in which the nozzles are mounted.
The present invention provides for an improved nozzle construction adapted to be mounted in a tubular lance connected to a supply of pressurized blowing medium whereby more efficient and effective cleaning is achieved employing the same quantity of blowing medium as compared to prior art nozzle constructions, or alternatively, whereby the same effective cleaning is obtained employing lesser quantities of blowing medium thereby providing for substantial reductions in the consumption of blowing medium to maintain heat exchange equipment in optimum operating condition.